1. Field of the Invention
The invention relates to a thin film device comprising an insulating film, a thin film magnetic head formed of a pair of shield gap films which are made of an insulating film with a magnetoresistive element in between, and a magnetoresistive element on which an insulating film is partially formed.
2. Description of the Related Art
Today, a composite thin film magnetic head is widely used as a thin film magnetic head. The composite thin film magnetic head has a layered structure which includes a recording head with an inductive-type magnetic transducer for writing and a reproducing head with a magnetoresistive (also referred as MR in the followings) element for reading-out. For example, as a reproducing head, an MR element is sandwiched by a pair of shield films with a pair of shield gap films in between, is popular. Each shield gap film is provided for electrically isolating the MR element and each shield film, and is made of, for example, aluminum oxide (Al2O3) with high insulating characteristic.
In such thin film magnetic head, performance improvement in a reproducing head has been sought in accordance with improvement in surface recording density of a hard disk drive in recent years. Methods of increasing reproducing output of a reproducing head are: increasing amount of sense current flowing into an MR element; and shortening the MR height. The MR height is the length (height) between the end of the air bearing surface (the surface facing the recording medium) side and the end of the other side.
If the amount of sense current flown into the MR element is increased, however, Joule heat generated by the resistance increases resulting in a rise in the temperature of the MR element. As a result, reproducing output decreases and the MR element may not last long. Also, if the MR height is made shorter, Joule heat generated by the resistance increases resulting in a rise in the temperature of the MR element. Accordingly, reproducing output decreases and the life of the MR element becomes shorter. Therefore, it is necessary to suppress a rise in the temperature of the MR element when increasing sense current or shortening the MR height.
In the related art, however, each shield gap film, which directly has a contact with the MR element, is made of aluminum oxide with a low thermal conductivity so that the heat generated in the MR element can not be effectively transmitted to each shield film. As a result, the heat of the MR element can not be effectively dissipated. In other words, a rise in the temperature of the MR element can not be suppressed so that the amount of sense current and the MR height are limited. Therefore, reproducing output can not be sufficiently improved.
Recently, to solve this problem, it is proposed in Japanese Patent laid-open Hei 5-205224 to form each shield gap film with aluminum nitride (AIN) or boron nitride (BN) with high thermal conductivity.
However, if the shield gap films are formed of aluminum nitride or the like, the shield gap films are further etched compared to the shield films and the MR element at the time of forming the air bearing surface by polishing. It is because aluminum nitride and the like are lower in hardness compared to aluminum oxide. As a result, there becomes a concave area in the air bearing surface.
Further, aluminum nitride or the like has a larger residual stress compared to aluminum oxide. Accordingly, if the shield gap film is formed of aluminum nitride, it becomes easy to exfoliate.
The invention has been designed to overcome the foregoing problems. The first object of the invention is to provide a thin film device, a thin film magnetic head and a magnetoresistive element in which the thermal conductivity and the hardness of the insulating film are improved.
The second object of the invention is to provide a thin film device, a thin film magnetic head and a magnetoresistive element in which the thermal conductivity of the insulating film is improved while the stress is decreased.
A thin film device of the invention comprises an insulating film which includes nitride of at least one of aluminum, boron, silicon or carbon, and argon.
The thin film device of the invention comprises an insulating film which includes nitride of at least one of aluminum, boron, silicon or carbon, and argon. As a result, high thermal conductivity of the insulating film can be attained while higher hardness can also be attained compared to the case where argon is not included.
In a thin film device of the invention, for example, it is preferable that the insulating film includes argon within the range of 0.1 atomic % and 5.0 atomic %.
Another thin film device of the invention comprises an insulating film which includes nitride of at least one of aluminum, boron, silicon or carbon, and oxygen.
As another thin film device of the invention comprises an insulating film which includes nitride of at least one of aluminum, boron, silicon or carbon, and oxygen, high thermal conductivity of the insulating film can be attained while the stress is decreased compared to the case where oxygen is not included.
In another thin film device of the invention, at least part of oxygen included in the insulating film may be chemically combined to at least one of aluminum, boron, silicon, carbon or nitrogen.
In another thin film device of the invention, for example, it is preferable that the insulating film includes oxygen in the range of 1 atomic % and 25 atomic %, and more preferable to be in the range of 5 atomic % and 20 atomic %. It is most preferable that the insulating film includes oxygen in the range of 10 atomic % and 15 atomic %.
Furthermore, in another thin film device of the invention, the insulating film may include argon. In this case, high hardness of the insulating film can be attained.
A thin film magnetic head of the invention comprises: a magnetoresistive element; a first shield film and a second shield film placed to face each other with the magnetoresistive element in between to shield the magnetoresistive element; a first shield gap film provided between the first shield film and the magnetoresistive element; and a second shield gap film provided between the second shield film and the magnetoresistive element. In the thin film magnetic head, at least part of at least either the first shield gap film or the second shield gap film is formed of an insulating film which includes nitride of at least one of aluminum, boron, silicon or carbon, and argon.
In another thin film magnetic head of the invention, at least part of at least either the first shield gap film or the second shield gap film is formed of an insulating film which includes nitride of at least one of aluminum, boron, silicon or carbon, and argon. As a result, the thermal conductivity and the hardness of at least either the first shield gap film or the second shield gap film are improved. Therefore, the heat generated in the magnetoresistive element by sense current flown into the magnetoresistive element at the time of reading out information is effectively dissipated through the first shield gap film and the second shield gap film. In addition, excessive polishing of the first shield gap film and the second shield gap film can be avoided at the time of controlling the length of the magnetoresistive element by polishing.
Another thin film magnetic head of the invention comprises: a magnetoresistive element; a first shield film and a second shield film placed to face each other with the magnetoresistive element in between to shield the magnetoresistive element; a first shield gap film provided between the first shield film and the magnetoresistive element; and a second shield gap film provided between the second shield film and the magnetoresistive element. In the thin film magnetic head, at least part of at least either the first shield gap film or the second shield gap film is formed of an insulating film which includes nitride of at least one of aluminum, boron, silicon or carbon, and oxygen.
In another thin film magnetic head of the invention, at least part of at least either the first shield gap film or the second shield gap film is formed of an insulating film which includes nitride of at least one of aluminum, boron, silicon or carbon, and oxygen. As a result, the thermal conductivity of at least either the first shield gap film or the second shield gap film is improved while the stress is decreased. Therefore, the heat generated in the magnetoresistive element by sense current flown into the magnetoresistive element at the time of reading out information is effectively dissipated through the first shield gap film and the second shield gap film. In addition, exfoliation of the first shield gap film and the second shield gap film can be suppressed.
In another thin film magnetic head of the invention, argon may be further included in at least part of at least either the first shield gap film or the second shield gap film. In this case, thermal conductivity of the first and the second shield gap films can be increased.
A magnetoresistive element of the invention has an insulating film at least partially formed on it. The insulating film includes nitride of at least one of aluminum, boron, silicon or carbon, and argon.
In the magnetoresistive element of the invention, the insulating film includes nitride of at least one of aluminum, boron, silicon or carbon, and argon. As a result, the thermal conductivity and the hardness of the insulating film are improved. Therefore, the heat generated in the magnetoresistive element is effectively dissipated through the insulating film and the magnetoresistive element can be easily manufactured.
Another magnetoresistive element of the invention has an insulating at least partially formed on it. The insulating film includes nitride of at least one of aluminum, boron, silicon or carbon, and oxygen.
In the magnetoresistive element of the invention, the insulating film includes nitride of at least one of aluminum, boron, silicon or carbon, and oxygen. As a result, the thermal conductivity of the insulating film is improved while the stress is decreased. Therefore, the heat generated in the magnetoresistive element is effectively dissipated through the insulating film and exfoliation of the insulating film can be avoided.
In another magnetoresistive element of the invention, the insulating film may further include argon. In this case, the hardness of the insulating film can be increased.
Other and further objects, features and advantages of the invention will appear more fully from the following description.